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MASTER CONCRETE ENTERPRISE Ltd. | |
NIIZhB & Center for Modified Concrete
present
Modified High Performance Concrete
4. Characteristic features of MB concrete proportioning
4.1 Concrete mixture proportioning begins from choosing a type and a brand of a modifier. Required concrete mixture characteristics which may be estimated on the basis of the information in sections 2 and 3 are the choice criteria.
Then the following factors should be optimized:
proportion of cement and MB
total consumption of binder (cement + MB)
Proportion of cement and MB is generally indicated in MB percentage relative to cement weight.
MB dosage is to be set taking into account the requirements to concrete mixtures, as well as economy factor.
Generally, the recommended MB dosage is within the range of 8–12% of cement weight but in some cases it may be varied to meet technical and economic efficiency requirements.
4.2 When optimizing MB dosage and total consumption of binder by strength criterion, the following characteristic tendencies are to be considered:
compressive strength – total binder consumption and MB dosage dependance (Fig.26)
Figure 26
Dependence of Compressive Strength on Total Binder (Сement + MB) Amount at Constant Water Content
compressive strength–water/binder ratio (W/C+MB) and MB dosage dependence (Fig.27).
Figure 27
Dependence of Compressive Strength on Water–Binder Ratio and MB Dosage at Constant Binder (Cement + MB) Content
4.3 When optimizing MB dosage by concrete frostresistance criterion, the following is to be considered:
for concrete frostresistance brand up to F300 (resistance to 300 cycles freezing–thawing according Russian Standard ГОСТ 10060.0–95) without air entraining or gas forming admixtures MB dosage should not exceed 10% of cement weight;
for concrete frostresistance brand over F300 (resistance to over 300 cycles) MB dosage may exceed 10% of cement weight under the obligatory condition of introduction of air entraining or gas forming admixtures (together with modifier) into concrete mixture.
4.4 When MB dosage is optimized (on the basis of one of the approved proportioning methods) the optimal proportioning of other concrete mixture components is to be calculated.
Research Institute for Concrete and Reinforced Concrete
Center for Modified Concrete
109428, Russia, Moscow, 2 Institutskaya, 6
Tel.: (095) 171–0573, 174–7635, 174–7629, 174–7606
Fax: (095) 174–7591
Е-mail:mb@niizhb.ru; info@master-concrete.com
